# What is Phase diagram: Definition and 54 Discussions

For the use of this term in mathematics and physics, see phase portrait and phase space.
A phase diagram in physical chemistry, engineering, mineralogy, and materials science is a type of chart used to show conditions (pressure, temperature, volume, etc.) at which thermodynamically distinct phases (such as solid, liquid or gaseous states) occur and coexist at equilibrium.

View More On Wikipedia.org
1. ### A Spin Structure Factor Explained: Static & Dynamic

Hi, can somebody explain the spin structure factor (static and dynamic)? how is it related to the lattice symmetry(I m working with honeycomb)? How could I implement it easily? Thanks :)
2. ### A Phase diagram of Carbon at large electric fields.

I am wondering if the phase diagram of Carbon has been explored at very large electric fields. Can one make any theoretical guesses ? In specific I am interested in Pressure Vs Electric field and Electric field vs Temperature at fixed temperature and pressure respectively.
3. ### Chemistry Why does evaporating water cause some water to be cooled and form ice?

Answer: I know that when water evaporates, it absorbs heat, that's why the process is endothermic. I don't understand why the water would be cooled and some ice would form, when the water is supposed to evaporate. What causes some water to be separately cooled instead of evaporated? Thanks.
4. ### Deriving relations for a hard sphere phase diagram

Ornstein-Zernike states that ##h(r_{12}) = c(r_{12}) + \rho \int d\mathbf{r}_3 c(r_{13})h(r_{32})## which after a Fourier transform becomes ##\hat{C} (\mathbf{k}) = \frac{\hat{H}(\mathbf{k})}{1+\rho \hat{H}(\mathbf{k})}## However, I don't see how to simplify this to the second equation he has...
5. ### Water Phase Diagram: Mathematically Modeling and Validating

I notice that water phase diagrams provided online always seem to show a rather linear behaviour for the solid-liquid boundary (and an extremely steep slope). How is this modeled mathematically? Say we use the Clapeyron equation with ΔH and ΔV_m being constant, as online example problems (meant...
6. ### Hamiltonian mechanics: phase diagram

The issue here is that I don't know how to operate the final equations in order to get the phase diagram. I suppose some things are held constant so I can get a known curve such as an ellipse. I attach the solved part, I don't know how to go on.
7. ### Potential Energy vs x phase diagram

U(x) = - ∫Fdx = - (1/2)kx^2. T = (1/2)m(x')^2. E = (1/2)[m(x')^2 - kx^2]. We could write out the Lagrangian here, but the chapter this comes from (Taylor's Classical Mechanics 13.6) indicates we should probably write the Hamiltonian, H = T + U. As far as I can tell, this doesn't tell me a...
8. ### A Negative Pressure in Solid Phase Diagram of Water

Hi everyone! I am working with the theoretical solid phase diagram of water and I would like to know what negative pressure means. Thank you in advance!
9. ### How does specific volume play its role in the phase diagram?

So, I am casually sifting through a chapter in a thermodynamics textbook talking about the multiphase process that pure substances go through. I understand how the P-v and T-v diagram works and that out of the three properties (specific volume, temperature and pressure), two of them are...
10. ### Reading a Binary Phase Diagram (lever rule etc.)

Hello All, Wanted to see if I am approaching this problem correctly, I have an exam coming up and am pretty sure something like this will show up. Examine the phase diagram (phase.jpg) with a 20WT% A and 80WT%B which is allowed to cool slowly from liquid A) what temp does the first solid...
11. ### Interpreting Ternary Phase Diagram

Homework Statement From the phase diagram what can be said of the porosity, mechanical strength, and density of various materials in the diagram? Homework EquationsThe Attempt at a Solution I am having trouble finding research on the general properties of quartz, feldspaar, and clay mineral...
12. ### Phase diagram of water in real life

Hello, All substances that are either in the liquid or solid state have a small vapor pressure which implies that they are always slowly (solids especially) evaporating and turning into a gas (vapor). The phase diagrams of water and carbon dioxide indicate only states (P , V) of pressure and...
13. ### I Phase diagram of MI/SF transition Bose-Hubbard model

Hi all, I am currently doing an undergraduate research project on the Bose-Hubbard model with hardcore bosons, and I am studying it theoretically using the Monte Carlo Stochastic Series Expansion method. I would very much like to ask my supervisor this question, but he seems extremely busy...
14. ### I Determinant problem in an article about QCD phase diagram

Hi. I'm reading an article about QCD phase diagram. https://arxiv.org/abs/1005.4814. I want to derive eq(20), but I don't know how. Does anyone know how to derive this?
15. ### Effects of added carbon to Pb-Sb Phase diagram?

How would cooling curves of a Pb-Sb phase diagram get effected if the composition had an added .5% carbon wt. concentration? My guess would be by adding an increased concentration of carbon, this would result in a increased duration of cooling needed to reach the eutectic reaction line. Any...
16. ### Help determining phase diagram of Pb-Sb alloy

Hello, I'm new to the forums and hope this is the correct area to post this question: I've Recently conducted a lab in class where we melted an alloy of Pb-Sb in order to determine its cooling curve. We did two different weight compositions (11.2% Sb) and (17.5% Sb) and recorded their...
17. ### Why does external pressure on a liquid increase vapor pressure

I was reading an online chemistry textbook that said "when a liquid is subjected to hydrostatic pressure (for example, by an inert, non-dissolving gas that occupies the vapor space above the liquid surface), the vapor pressure of the liquid is slightly raised." (link...
18. ### Does Pressure in Phase Diagram refer to vapor pressure?

I am somewhat confused by what pressure refers to in a phase diagram? In a closed box it makes sense to me that the vapor pressure would eventually equilibriate at a pressure determined by the temperature. However, say you have an open box. It makes sense that the liquid would boil when the...
19. ### Phase Diagram of Steel with unknown C content

Homework Statement Given that the overall weight percentage of ferrite along the grain boundaries of an as-cast steel with unknown C amount is 35.23%: a) Identify if it is hypoeutectoid or hypereutectoid. b) Identify the amount of carbon alloyed in the steel. c) Identify how much ferrite and...
20. ### Phase diagram p-v and plasmatic state

phase diagrams show the change of the state when temperature or pressure are modified. to achieve this, is necessary heat, but my questions is: would plasma state be described in this diagrams? is this figure true? because plasma state can be generated by heating.
21. ### Phase Diagram Question: How to Solve with Ease | No Template Needed

THIS HOMEWORK WAS PLACED INCORRECTLY IN ANOTHER FORUM, SO THERE IS NO TEMPLATE (AND NO EFFORT) I have no idea how to tackle this. Please show me how to do these problems.
22. ### Need help reading a phase diagram for a lipid DMPC

Homework Statement Homework Equations None required? The Attempt at a Solution I understand that Id would be a disordered phase, Io an ordered phase and the other two are regions where 2 phases exist at the same time possible due to cholestrol. I am assuming so means solid ordered. But...
23. ### Questions Regarding the Phase Diagram

Hello I’m wondering if my understanding of how different processes relate to the phase diagram here is correct. 1) If a piston cylinder assembly maintains a constant 1atm pressure on some water and the water is cooled, we would be going horizontally along the red line from 373.15K to 273.15K...
24. ### Phase Diagram of BiMnO3: High Pressure Necessary?

HELLO everyone.. i have read some journals and some researchers (not all but most of them) said that bismuth manganate MUST be synthesized in high pressure conditions. in other words, not in room temperature/pressure. it that true? because some of researchers also synthesized that BiMnO3 in...
25. ### Best way to present a phase diagram of a 4 component system

Hullo, I've just only begun looking at phase diagrams of a 5 component alloy and wanted to know if there is a better way to study the phase diagrams of multi-component alloys rather than looking at a multitlude of binary phase diagrams calculated from the alloy system. I'm using Thermocalc...
26. ### Oxygen Phase Diagram: Pressure & Liquefy 0-50 atm

i need to know what pressure oxygen will liquefy at under various pressures but i can't find a phase diagram anywhere any link phase diagram that shows pressures 0-50 atm would be useful
27. ### Pressure on (T,P) Phase Diagram for Substance

On a (T,P) phase diagram, what is meant by the pressure at each phase for the substance? Chemically speaking we are only usually dealing with "gaseous" pressure (i.e. that exerted by the gases), but only when the substance is in (one of the phases in) the gaseous state or supercritical fluid...
28. ### Phase Diagram Composition Determination

Homework Statement Reference the Cu-Zr phase diagram. If you make the alloy CuZr and heat it to 300°C, what percentage of the material will be Cu10Zr7 and what percentage of the material will be CuZr2? Homework Equations Phase diagram attached. The Attempt at a Solution I used the lever...
29. ### Thermodynamics Binary Phase Diagram Problem

Homework Statement Refer to the attached binary phase diagram. Substance A has a melting point of 600 °C and B has a melting point of 1200 °C. A mixture of 70 weight percent B and 30 weight percent A is held at 950 °C for a long time - long enough to reach equilibrium. a) Determine the weight...
30. ### Where Can I Find a Pressure-Temperature Phase Diagram for Pure Methanol?

PLEASE! I need to find a pressure-temperature phase diagram por PURE methanol! it's driving me mad...
31. ### Can a Solid Have Lower Free Energy than a Liquid at Low Packing Densities?

In a nutshell, I am trying to see how to derive the conditions of coexistence between a solid and a liquid from a phase diagram. The situation is as follows: Consider a mixture of hard spheres of diameter σ. The potential energy for a hard sphere system is given by \beta U(r) = 0 (r > \sigma)...
32. ### Is the phase diagram for an oscilliator always clockwise?

Is the phase diagram for an oscilliator (all sorts of oscilliations) always clockwise? If it is so, why?
33. ### Phase diagram H2O saturation pressure

Homework Statement Suppose 2 kg of H2O at 200 C and 300 kPa are contained in a weighted piston cylinder assembly. As a result of heating at constant pressure, the temperature of the H2O increases to 400 C. Determine the change in volume, the change in internal energy, and the change in...
34. ### Phase diagram contradiction: why does vapor exist?

When you learn about phase diagrams of pure substances, you learn that the liquid and gas phases are in equilibrium only along the line separating the pure liquid and pure gas regions. But if you have a sample of liquid in a closed container with some empty space in it, that empty space...
35. ### Al-W Phase Diagram: Research & Info Source

hey all. i am doing some research about the Al-W system. and i wanted to find out how the diagram was made. i searched and found who made it - Clark W.D.: "THE ALUMINIUM-TUNGSTEN EQUILIBRIUM DIAGRAM", J. Inst. Met. 66 (1940) 271–286. but i can't find any more info , and i cand...
36. ### Where is the Phase Diagram for X and XDot?

phase diagram for x and xdot.
37. ### Phase Diagram Database: Open Access Sources?

I've been searching the web with no luck - are there any open phase diagram databases available, preferably for temp-pressure-volume?
38. ### Phase Diagram of Simple Pendulum Relationship and Plotting Process Explained

Homework Statement The relationship between velocity and position of a simple pendulum is given by the equation y= \pm\sqrt(2(C+\omega^2 cos x)). The corresponding phase diagram is attached. How on Earth did they come up with the phase diagram. How do you plot such a complicated equation...
39. ### Light reflected from film, find maximum thickness of film, draw phase diagram.

Homework Statement The light reflected from a soap bubble (n=1.4) appears bright red (wave length= 640 nm) at its center. What is the minimum thickness (in nm) there? Dray Phase Diagram. Homework Equations lambda(n)=lambda/n n=index of refraction 2*n*t=m*lambda OR 2*n*t...
40. ### Ideal solution phase diagram computation

Homework Statement Hi there, I'm very new here and I was hoping someone would be able to help me out a bit! I have a few questions but right now I'm going to start with this problem. Elements A and B form ideal solutions in both liquid and solid phases. Compute the A-B phase diagram using...
41. ### Water Phase Diagram: Is Vapour-Ice Coexistence at 0K, 0Pa?

Is it true that the line of coexistence of water vapour and ice starts from the point p=0, T=0?
42. ### What are the phases present after quenching a sample of 1040 steel?

Homework Statement http://img641.imageshack.us/img641/1996/graphyw.png Homework Equations [PLAIN]http://img140.imageshack.us/img140/4379/5400ad3870194a9786484cb.gif [PLAIN][PLAIN]http://img17.imageshack.us/img17/2517/4bb673fefcbe473fa83e468.gif The Attempt at a Solution I...
43. ### How to draw the Isothermal Section of a Ternary Phase Diagram

Professor is now teaching us to draw isothermal sections of a Ternary Phase Diagram... Isothermal Section: A “horizontal” section of a ternary phase diagram obtained by cutting through the space diagram at a specified temperature I am so confused... I have big trouble in picturing the...

45. ### Understanding Phase Diagrams: Impact of Pressure Changes on a System

When looking at a phase diagram and the effect of an increase or decrease in pressure- are we assuming that work is being done on the system?
46. ### Solid solution phase diagram.

Hi,I'm sorry to be back with all my questions after almost 2 months,but inspite of all my books and websites, I can't find any complete description of phase diagrams of solid solutions and of peritectic mixtures. I have my exams next week,so please try and help me within that period...as soon...
47. ### Phase diagram of Ag - Cu question

Homework Statement Describe equilibrium cooling from 1200 C to 200 C of an alloy containing 40 wt% Ag. Draw the schematic equilibrium cooling curve The Attempt at a Solution Alloy begins as a liquid, begins to solidify as temperature reaches the liquidus line; alpha accumulates and the...
48. ### Understanding Ternary Phase Diagrams for Inverted Micelle Formation

Will someone please explain how one can read from this diagram that the composition is 9% NaC(8), 28% water and 63% C(10)OH when we have the smallest amount of C(10)OH to have inverted micelles in the system?
49. ### Construct Binary Phase Diagram from Ternary Phase Diagram

Hi all, I need some help on the ternary phase diagram. What I'm trying to do is get a binary phase diagram from the ternary phase diagram, like the one shown in the first picture. I been set a question of getting the phase BO (second picture), not the usual AB, BC etc.. How do I construct...
50. ### The other end water phase diagram

where does sublimation curve intercept temp axis?